It is often required, when performing a biochemical reaction, to pass a liquid or a gaseous medium containing reagents or nutrients though a chamber in which a reagent or a catalyst in the form of biological macromolecules is substantially uniformly distributed in fixed, but spaced-apart, locations. For this purpose it is necessary to support the biological macromolecules in a material which mobilizes and protects the biological macromolecules whilst permitting free passage of the medium through the chamber.
Porous inorganic materials in the form of beads, granules or particles of more irregular shape have been used to support biological macromolecules. If the inorganic materials are to be used to pack a large column in which a biochemical reaction is to be carried out on a commercial scale, it is necessary for the material to be sufficiently porous to provide cavities in which the biological macromolecules can be immobilised, while retaining sufficient mechanical strength to resist the crushing effect of the weight of the packing material in the column.